Ectromelia virus, an orthopoxvirus that can cause extensive morbidity (mousepox) in colonized mice, has been epizootically responsible for serious disruptions of biomedical research since 1930. The last outbreak of mousepox at NIH, which began in 1979, was estimated to have cost more than one million dollars in surveillance and control efforts. The cost in thwarted and delayed experiments cannot be estimated. The goals of this proposal were to: (1) develop a sensitive and specific serologic assay using the principles of the enzyme-linked immunoabsorbent assay (ELISA); (2) study the kinetics of natural transmission (including clinical response) among commonly used strains of inbred mice, such as BALB/cByJ, C57BL/6J, and DBA/2J; (3) measure the efficacy of immunity induced by the IHD-T strain of vaccinia virus in BALB/cByJ mice; (4) evaluate the risk of virus transmission through mouse-derived tumors (hybridomas) and sera; (5) undertake preliminary studies on the genetics of innate resistance in outbred (Mus cervicolor popaeus, Mus platythrix, Mus pahari, Mus spretus, Mus musculus, and Mus domesticus) and inbred mouse populations (C57BL/6J, BALB/cByJ, A/J, DBA/2J); (6) study the epizootiology of naturally occurring outbreaks of mousepox; and (7) correlate various ectromelia biological strain (strains: Beijing 78, Ishibashi, St. Louis, Wash. U., Moscow) differences to DNA genome sequence which will aid in the studies of epizootics. Of the above mentioned goals, the first five have been completed and are either in press or in various stages of preparation for publication. It is anticipated that the remaining two goals will be finished in 1983-1984 fiscal year. The basic studies and diagnostic methodology described above are essential for a rational approach to the control and prevention of mousepox, which threatens serious disruption of biomedical research in the U.S.